The Mohawk people of Akwesasne live in an area of high environmental pollution which appears to be affecting their diet, economy and way of life. Known high levels of polychlorinated biphenyls (PCBs) are believed to be affecting their physical and psychological well-being. The primary purpose of this study is to examine the extent to which exposure to PCBs as determined by body burden levels and perceived impact of the exposure, affect cultural identity and practices, neuropsychological functioning and quality of life. The study will also examine the extent to which these factors are related to depression and psychological distress. The specific aims are: (1) to examine the relationships among PCB exposure, major depression, and depressive symptoms; (2) to examine the relationships among PCB exposure, neuropsychological functioning, depression, and depressive symptoms; (3) to examine the relationships among PCB exposure, thyroid functioning, neuropsychological functioning and depression; (4) to examine the extent to which cultural practices have been altered as a result of exposure to PCBs; (5) to examine the relationships among quality of life factors, depression and depressive symptoms, and neuropsychological function; (6) to examine the extent to which major life events and their perceived impact are related to depression and depressive symptoms; (7) to examine the extent to which cultural identification and practices are predisposing vulnerability factors or buffers against the adverse effects of exposure to PCBs; and (8) to determine the most effective way of disseminating research findings to the community and assist in developing community outreach interventions.